Heat Loss in gas flow through Pipe

[matthew_knight]

Hi,

I'm trying to work out a formula for calculating the heat loss of hot air flowing through a pipe in cold air, so that eventually I can spec the length of pipe needed.
It's been a while since I'v done any thermodynamics so some help would really be appreciated. I've summarised the problem in the image bellow.




I thought about doing an iterative solution like bellow, but am struggling to understand which formulas I should be combining to account for heat loss to environment and heat flow along pipe.


​

Thanks,

Matt

[Kelly_Bramble]

See:

https://www.engineersedge.com/heat_t...pipe_13841.htm

and

https://www.engineersedge.com/heat_t...le_content.htm